1. Field of the Invention
The present invention relates to a hydraulic accumulator pressure release valve and more particularly to such a release valve that is hydraulically operated.
2. Description of the Prior Art
Hydraulic pressure accumulators are commonly used in hydraulic power systems to help maintain system pressure despite variations in demand or pump discharge pressures. As a safety measure, it is desirable to include an accumulator pressure release valve in such a hydraulic power system to release accumulator and system pressure whenever the system's pump is deactivated. Without such a release valve, the accumulator maintains residual pressure in the system even though the system appears to be inoperative because the pump is shut off. Under such circumstances someone cleaning or maintaining hydraulically operated tools or machinery could inadvertently actuate the system, possibly damaging it or causing bodily injury.
Although accumulator pressure release valves are commonly used in such hydraulic systems, in the past such valves have been electrically operated. Electrically operated valves naturally require a separate electrical system for their operation, adding significantly to the cost of the hydraulic power supply unit and rendering the functioning of such valves dependent on the functioning and reliability of the electrical system.